speed is a factor because if you're going 15 mph you'll be able to stop when you bump into something and not have a very high risk of killing it... you also have a lot more time to look around and see any potential conflicts...

I agree on the point of speed, and and thus inertia, being a critical factor in injury vs fatality.
I also agree that all vehicle operators need to slow down; even cyclists on cobblestone residential streets

The thing is that I see this as indemic of a more systemic issue of the auto culture in its entirety.
Similar to stale competitive genetic software algorithms or the saber toothed cat the automobile is a solution to a problem that no longer exists in its original form yet all current descendants of the original automobiles are hobbled by the all the same deficiencies.
It is designed for solitary use in wide open spaces away from anything that might suddenly get in the way.
As is evidenced by old wacky laws about horseless carriage operators being required to have a lantern holder walk many yards in front of the driver night driving is difficult and inherently dangerous to the point of near impossibility without large headlights.
Again, in isolation this isn't a problem but as soon as two sets of headlights met the end was written in stone. Our eyes are simply not designed to effectively gather accurate data in the dark with a bright glare constricting one's irises.
But this didn't matter because by the time the public was driving after dark on a regular basis we were already addicted.
So we are stuck with an engineering problem veneered around a societal one: we are economically and geographically dependent upon autos driven by operators that are simply incapable of avoiding every avoidable collision.

Hopefully Google's self driving car will help shift this stagnant paradigm away from distracted drivers unable to perform the task to a system where everyone that insists on manually driving their car will pay through the nose for the privilege of doing so.